Submarine dredge



I. N. DAWSON. SUBMARINE DREDGB- APPLICATION nuzn JULY 3|. I920.

Patented Mar. 1, 1921.

2 SHEETS-SHEET l- 6/2101), fiaws'aiq J. N. DAWSON.

SUBMARINE DREDGE.

APPLICATION FILED JULY 31, I920.

2 SHEETS-SHEET 2.

Patented Mar. 1,1921.

UNITED STATES PATENT OFFICE.

JOHN N. DAWSON,'OF SEATTLE, WASHINGTON, ASSIGNOR, BY MESNE ASSIGNMENTS,

' TO DEEP WATER SALVAGE AND DRYDOGK COMPANY, OF SEATTLE,

A CORPORATION.

SUBMARINE DREDGE.

Specification of Letters Patent.

Patented Mar. 1, 1921.

To all whom it may concern:

Be it known that I, Join: N. DAWSON, a

- citizen of the United States. and residing at Seattle, in the county of King and State of Washington, have invented certain new and useful Improvements in Submarine Dredges, of which the following is a specification.

This invention relates to apparatus for submarine dredging.

An object of the inventlon is 'to prov de an excavator which will dig the dirt away from under a sunken vesseliiwhich is desiredto be salvaged and allow thelifting cables to be placed thereunder without the aid or a diver.

Another object of the invention is to provide means for guiding the excavator and cause it to take a bite in. the earth.

This invention also comprehends other objects which are particularly pointed out in the following description and claims.

In the drawings Figure 1 is a view of the apparatus 1n operative position at the bow of a sunken vessel.

Fig. 2 is a side elevation of the sunken vessel showing the earth scooped away from under the bow and stern of the vessel to allow the placing of the lifting cables.

Fig. 3 is a side elevationof the excavator, a portion being shown broken away.

Fig. 4.- is an end view of the excavator.

1 indicates a sunken vessel which is desired to be saved and 2 indicates tug boats which are designed to carry the apparatus hereafter described, and to operate said ap paratus for excavating the dirt from under the sunken vessel.

3 indicates an excavator formed in halves divided longitudinally, and provided with flanges 4 whereby the halves may be secured together by bolts 5. The excavator is cylindrical in shape throughout the central portion thereof,.and is flared ateach end as indicated at'6. Each end of the excavator is recessed as shown at 7, said recess extending outwardly to the edge thereof to provide a sharp cutting edge 8, and each half of the excavator is recessed at 9 to receive the central portion of a cable 10 to which the excavator is securely fastened. The excavator as above stated is secured to the central portion of the cable 10, each end of said cable being secured to one of the tugs 2. Weights 11 are secured to the cable on each side of the excavator and spaced a slight distance therefrom, and are for the purpose of pulling the end of the excavator down on the earth, so that it will take a bite in the movement thereof in either direction. These weights are rounded at the ends as shown, so that they will ride back and forth without catching on obstructions which might be in their path. Some distance beyond the weights 11' are placed stationar weights 12 which carry blocks 13 in whic the cable is slidably mounted, and which hold the cable which carries the weights 11 and the excavator on the bottom of the sea. The ends of the. cable beyond the weights extend upwardly to the tugs as shown.

In order to place the lifting cable under a sunken vessel, it is first necessary to excavate the dirt from beneath the bow and stern of the vessel. Two tugs carrying the above described apparatus locate the sunken vessel by sounding and find the location of the bow and stern. Then they drop the excavator and the weights overboard, so that they will rest on the bottom near the bow or the stern as desired. The weights 12 are positioned by lines 14 in a line at right angles to the fore and aft line of the sunken vessel and spaced a distance from the vessel as shown in Fig. 1, the excavator being located between the weights and adjacent.the bow of the vessel. One of the tugs 2 now pulls ahead on its end of the cable and pulls the excavator toward one of the weights 12 until the weight 11 contacts with the weight 12. It then reverses its direction and slacks the cable, whereupon the other tug goes forward in the opposite direction and pulls the excavator across the bow of the sunken vessel toward the other weight 12. This operation is continued until all the dirt is scooped away from under the bow of the vessel as indicated in Fig. 2, the weights 12 being occasionally adjusted to move the excavator so that it will dig under the bow WASHINGTON,

In the use of an apparatus of this kind, it will be seen,that the services of a diver are entirely unnecessary, and that the excavator will efiicientl Y remove the dirt from'under the bow and stern of the vessel, being guided in its operation by the weights 11, and that the lifting cables may be easily placed under the bow and stern without danger of them slipping, due ,to improper positioning thereof.

What I claim is f 1. A submarine excavatin apparatus :omprising an excavator, a cablehaving the central portion secured to saidexcavator wei ghts mounted on the cable at each side of the excavator and slightly 5 aced therefrom, stationary weights place beyond the first-mentioned weights, and in which the cable is slidably mounted, and means for producin a retrograde movement of the cable an excavator between the stationary weights.

2. A submarine excavating apparatus comprising a cable, an excavator secured in the central portion thereof, means mounted on the cable for guiding the excavator, weights located beyond the guiding means in which the cable is slidably mounted, and means for moving the excavator back and forth between the weights.

3. A submarine dredging apparatus comcentra portion thereof, said excavator being formed of a cylindrical member having I flared end portions and recessed in the ends, the recess extending outwardly to the periphery of the flared end portions to form a cutting prisin a, cable, an excavator secured to the edge, weights secured to the cable on each side of the excavator and spaced therebeing enlarged at the extreme ends and terminating in a cutting ed e with the flared port on, and each half bemg formed with a longitudinal oove for receiving the central portion of the cable, weights secured to the cable on each side of the excavator, stationary weights placed beyond the abovementioned weights in WhlOh the cable is slidably mounted, and means for producing retrograde movement of the excavator.

In testimony whereof Iaflix my signature.

I JoHN N. DAWSON. 

